Solar cell module

ABSTRACT

In the solar cell module  100 , the insulating sheet  15  has the slit  151  which is in contact with the output lead  12  inside the opening portion  141  of the rear-surface-side protection member  14.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority fromprior Japanese Patent Application No. 2009-070354, filed on Mar. 23,2009; the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a solar cell module including an outputlead configured to draw electric power from the solar cell.

2. Description of the Related Art

A solar cell is expected as a new energy source because the solar celldirectly converts clean and inexhaustibly supplied sunlight intoelectricity. Generally, in order to increase the weather resistance of asolar cell, the solar cell is sealed with a sealing member between alight-receiving-surface-side protection member and a rear-surface-sideprotection member. As the rear-surface-side protection member, alaminated film in which a metal layer such as aluminum layer issandwiched between resin layers is also widely used to improve themoisture resistance thereof.

Electric power generated by such solar cell is drawn to the outside ofthe solar cell module by an output lead connected to the solar cell.Specifically, the output lead is drawn out to the outside of the solarcell module through an opening portion formed in the rear-surface-sideprotection member.

In this process, a technique has been proposed to cover a part of themetal layer with an insulating film and draw the output lead along theinsulating film (refer to Japanese Utility Model RegistrationApplication Publication No. Hei 3-63954). According to this technique,electrical insulation between the metal layer exposed to the openingportion and the output lead can be improved.

However, with the technique described in Japanese Utility ModelRegistration Application Publication No. Hei 3-63954, the metal layerexposed in the opening portion and the output lead are adjacent to eachother with the insulating film interposed therebetween. Thus, theelectrical insulation may not be secured if the solar cell module has ahigh output.

The invention is made in view of the above-mentioned problem, and it isan object of the invention to provide a solar cell module capable ofsecuring electrical insulation between a metal layer of arear-surface-side protection member and an output lead.

SUMMARY OF THE INVENTION

An aspect of the present invention is summarized as a solar cell modulecomprising: a solar cell having a light receiving surface and a rearsurface provided on the opposite side to the light receiving surface; anoutput lead configured to draw electric power from the solar cell; alight-receiving-surface-side protection member disposed on thelight-receiving-surface-side of the solar cell; a rear-surface-sideprotection member disposed on the rear-surface-side of the solar celland having an opening portion through which the output lead is drawnout; and an insulating sheet disposed on the opening portion; andwherein the rear-surface-side protection member includes a metal layersandwiched between a plurality of resin layers, and the insulating sheetincludes a contact portion which is in contact with the output leadinside the opening portion in a plan view.

In the above aspect of the present invention, it is preferable that theinsulating sheet is formed of a pair of sheets sandwiching therear-surface-side protection member, and the contact portion is a slitformed in the insulating sheet.

In the above aspect of the present invention, it is preferable that theinsulating sheet covers the opening portion at the solar cell side ofthe rear-surface-side protection member.

In the above aspect of the present invention, it is preferable that theinsulating sheet covers the opening portion at the opposite side of therear-surface-side protection member to the solar cell.

In the above aspect of the present invention, it is preferable that adistance between an outer edge of the insulating sheet and an outer edgeof the opening portion is greater than a thickness of therear-surface-side protection member.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a solar cell module 100 according to a firstembodiment of the invention.

FIG. 2 is a plan view from the rear-surface-side protection member 14 ofthe solar cell module 100 according to the embodiment of the invention.

FIG. 3 is a cross-sectional view taken along the line A-A of FIG. 2.

FIG. 4 is an exploded cross-sectional view illustrating a manufacturingmethod of the solar cell module 100 according to the embodiment of theinvention.

FIGS. 5A and 5B are a plan view and a cross-sectional view illustratingthe configuration of an insulating sheet 20 according to the embodimentof the invention, respectively.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Next, the embodiments of the invention are described with reference tothe drawings. In the following description of the drawings, identical orsimilar reference numerals are assigned to identical or similarcomponents. However, the drawings are schematic, thus it should be notedthat the dimensions are not shown to scale. Accordingly, specificdimensions should be recognized in consideration of the followingdescription. Also, there are inevitably included some portions of thedrawings between which a dimensional relationship and/or a scale areinconsistent.

[Schematic Configuration of Solar Cell Module]

The schematic configuration of a solar cell module 100 according to anembodiment of the invention is described with reference to FIG. 1. FIG.1 is a side view of the solar cell module 100 according to theembodiment of the invention.

As shown in FIG. 1, the solar cell module 100 includes plurality ofsolar cells 10, a plurality of connecting members 11, an output lead 12,a light-receiving-surface-side protection member 13, a rear-surface-sideprotection member 14, an insulating sheet 15, and a sealing member 17.The solar cell module 100 is formed by sealing the plurality of solarcells 10 between the light-receiving-surface-side protection member 13and the rear-surface-side protection member 14.

The plurality of solar cells 10 are arranged in a matrix form betweenthe light-receiving-surface-side protection member 13 and therear-surface-side protection member 14. The plurality of solar cells 10are electrically connected by the plurality of connecting members 11.Each solar cell 10 has a light receiving surface configured to receivelight and a rear surface provided on the opposite side of the solar cell10 to the light receiving surface. Although not shown, there areprovided in each solar cell 10, a photoelectric conversion partconfigured to generate a carrier by receiving light on the lightreceiving surface, and a pair of positive and negative electrodesconfigured to draw the career from the photoelectric conversion part.

Each of the plurality of connecting members 11 is connected to anelectrode formed on the light receiving surface of one solar cell 10,and an electrode formed on the rear surface of another solar cell 10adjacent to the one solar cell 10. Thereby, the one solar cell 10 andthe other solar cell 10 are electrically connected to each other. Eachconnecting member 11 is preferably formed of a thin plate or a twistedwire of a material having a low electrical resistance such as copper,silver, gold, tin, nickel, aluminum, or an alloy of these. The surfaceof each connecting member 11 may be formed with a conductive materialsuch as lead-free solder (e.g., SnAg_(3.0)Cu_(0.5) solder).

The output lead 12 is a wiring member configured to draw the electricpower generated by the plurality of solar cells 10 to the outsidethereof. One end of the output lead 12 is electrically connected to anelectrode of at least one solar cell 10. The other end of the outputlead 12 is inserted through an insulating sheet 15 disposed on anopening portion 141, and is connected to a connecting terminal in anunillustrated terminal box. Although not shown, a pair of positive andnegative output leads is generally provided in the solar cell module 100(not shown in FIG. 1, see FIG. 2).

Similarly to the connecting member 11, the output lead 12 is preferablyformed of a material having a low electrical resistance. Also, theoutput lead 12 is covered with an insulating film.

The light-receiving-surface-side protection member 13 is disposed on thelight-receiving-surface-side of a plurality of solar cells 10. Thelight-receiving-surface-side protection member 13 protects the surfaceof the solar cell module 100. As the light-receiving-surface-sideprotection member 13, a glass which has a translucency and animperviousness to water or a translucent plastic may be used.

The rear-surface-side protection member 14 is disposed on therear-surface-side of the plurality of solar cells 10. Therear-surface-side protection member 14 protects the rear surface of thesolar cell module 100. The rear-surface-side protection member 14according to the embodiment has a structure in which a metal layer issandwiched between two resin layers. The rear-surface-side protectionmember 14 has the opening portion 141 through which the other end of theoutput lead 12 is drawn out to the outside of the solar cell module.

The insulating sheet 15 is disposed at the opening portion 141 of therear-surface-side protection member 14. In the embodiment, theinsulating sheet 15 is formed of a pair of sheets sandwiching therear-surface-side protection member 14, and covers both sides of theopening portion 141. The output lead 12 is inserted through theinsulating sheet 15.

The sealing member 17 seals the plurality of solar cells 10 between thelight-receiving-surface-side protection member 13 and therear-surface-side protection member 14. As the sealing member 17,translucent resin such as EVA, EEA, PVB, silicon, urethane, acryl, andepoxy may be used.

An Al frame may be mounted on the outer circumference of the solar cellmodule 100 which has the above configuration.

[Configuration of Rear Surface Side Protection Member and InsulatingSheet]

Next, the configurations of the rear-surface-side protection member 14and the insulating sheet 15 are described with reference to FIGS. 2 and3. FIG. 2 is a plan view from the rear-surface-side protection member 14of the solar cell module 100 according to the embodiment of theinvention. FIG. 3 is a cross-sectional view taken along the line A-A ofFIG. 2.

As shown in FIG. 2, the opening portion 141 of the rear-surface-sideprotection member 14 is covered with the insulating sheet 15. At theinsulating sheet 15, there is formed a slit 151, through which a pair ofthe output leads 12 are drawn out.

The slit 151 is in contact with the pair of output leads 12. The slit151 is formed inside the opening portion 141 in the plan view.Accordingly, the base portion of the pair of output leads 12 is fixedwithin the opening portion 141 by contacting against the slit 151. Itshould be noted that the slit 151 is the “contact portion” according tothe invention.

As shown in FIG. 3, the rear-surface-side protection member 14 is formedof a first resin layer 14 a, a metal layer 14 b, and a second resinlayer 14 c. The metal layer 14 b is sandwiched between the first resinlayer 14 a and the second resin layer 14 c. The first resin layer 14 aand the second resin layer 14 c are sheet-like resin films such as a PETfilm, for example. The metal layer 14 b is an aluminum foil, forexample. The metal layer 14 b is exposed on the inwall of the openingportion 141.

As shown in FIG. 3, the insulating sheet 15 according to the embodimentis formed of a pair of a first sheet 15 a and a second sheet 15 b.

The first sheet 15 a covers the opening portion 141 at the solar cell 10side of the rear-surface-side protection member 14. The second sheet 15b covers the opening portion 141 at the opposite side of therear-surface-side protection member 14 to the solar cell 10. The firstsheet 15 a and the second sheet 15 b may be in direct contact withrespective surfaces of the rear-surface-side protection member 14.

As each of the first sheet 15 a and the second sheet 15 b, an insulatingresin sheet or a rubber sheet may be used, for example. Although thefirst sheet 15 a and the second sheet 15 b need not to be elastic, butpreferably have moderate flexibility.

The first sheet 15 a and the second sheet 15 b are connected to eachother inside the opening portion 141. The slit 151 is formed in theconnecting portion between the first sheet 15 a and the second sheet 15b of the insulating sheet 15.

Specifically, the slit 151 is spaced away from the inwall of the openingportion 141 as shown in FIGS. 2 and 3. That is, the slit 151 is formedinside the opening portion 141, and is spaced away from the metal layer14 b exposed on the inwall of the opening portion 141. Thus, the outputleads 12 inserted through the slit 151 are fixed to a position spacedaway from the metal layer 14 b.

In the embodiment, it should be noted that the distance a between theouter edge of the insulating sheet 15 and the outer edge of the openingportion 141 is greater than the thickness β of the rear-surface-sideprotection member 14 as shown in FIG. 3.

[Manufacturing Method of Solar Cell Module]

Next, a manufacturing method of the solar cell module 100 is describedwith reference to the drawings. FIG. 4 is an exploded sectional view ofthe solar cell module 100 before it is modularized.

First, the plurality of solar cells 10 arranged in a matrix form areelectrically connected with the connecting member 11.

Next, one end of the output lead 12 is electrically connected to atleast one solar cell 10.

Next, a slit is formed through the sealing member 17 b in the thicknessdirection for the output lead 12 to be inserted through the slit.

Next, the opening portion 141 is formed in the rear-surface-sideprotection member 14 by removing a portion thereof.

Next, respective center portions of the first sheet 15 a and the secondsheet 15 b are bonded to each other. The slit 151 is then formed bymaking a linear cut at the connecting portion between the first sheet 15a and the second sheet 15 b. Thus, the insulating sheet 15 is prepared.

Next, the insulating sheet 15 is fitted into the opening portion 141 soas to sandwich the rear-surface-side protection member 14 by the firstsheet 15 a and the second sheet 15 b.

Next, a laminated body is formed by sequentially laminating thelight-receiving-surface-side protection member 13, the sealing member 17a, the plurality of solar cells 10, the sealing member 17 b, and therear-surface-side protection member 14. In this step, as shown in FIG.4, the output lead 12 is drawn out through the slit of sealing member 17b and the slit 151 of the insulating sheet 15.

Next, the laminated body is heated in a predetermined condition in avacuum atmosphere. Thereby, the sealing member 17 is cured.

OPERATION AND EFFECT

In the solar cell module 100 according to the embodiment, the insulatingsheet 15 has the slit 151 which is in contact with the output lead 12inside the opening portion 141 of the rear-surface-side protectionmember 14.

Accordingly, the base portion of the output lead 12 is fixed within theopening portion 141 by contacting against the slit 151. Thus, the outputlead 12 can be spaced away from the metal layer 14 b exposed on theinwall of the opening portion 141. As a result, the electricalinsulation between the output lead 12 and the metal layer 14 b can besecured, thus, reduction in insulation performance of the solar cellmodule can be prevented.

In the solar cell module 100 according to the embodiment, the firstsheet 15 a covers the opening portion 141 at the solar cell 10 side ofthe rear-surface-side protection member 14. Thus, even if the outputlead 12 is drawn along the rear-surface-side protection member 14 insidethe solar cell module 100, contact of the output lead 12 with the metallayer 14 b can be avoided. Accordingly, a degree of freedom ofarrangement of the output lead 12 can be improved. Also, permeation ofwater into the solar cell module 100 can be prevented by the first sheet15 a.

In the solar cell module 100 according to the embodiment, the secondsheet 15 b covers the opening portion 141 at the opposite side of therear-surface-side protection member 14 to the solar cell 10. Thus, evenif the output lead 12 is turned back outside the solar cell module 100,contact of the output lead 12 with the metal layer 14 b can be avoided.Also, permeation of water into the solar cell module 100 can beprevented by the second sheet 15 b.

Other Embodiments

Although the invention has been described according to the aboveembodiments, it should be understood that the discussion and drawingswhich form part of the disclosure are not intended to limit theinvention. Various alternative embodiments, implementation examples, andapplication techniques will be apparent to those skilled in the art.

For example, in the embodiment described above, the insulating sheet 15is formed of the pair of the first sheet 15 a and the second sheet 15 b,however; the invention is not limited to this configuration. Forexample, the insulating sheet 15 may be formed of either one of the pairof the first sheet 15 a and the second sheet 15 b. Even in this case,the output lead 12 can be spaced away from the metal layer 14 b exposedon the inwall of the opening portion 141 by forming the slit 151 in oneof the sheets.

In the embodiment described above, as an example of a contact portionaccording to the invention, the slit 151 formed in the insulating sheet15 has been described; however, the invention is not limited to thisconfiguration. At a contact portion according to the invention, the baseportion of the output leads 12 is only needs to be fixed to a positionspaced away from the metal layer 14 b exposed on the inwall of theopening portion 141. Thus, the insulating sheet 20 does not need tocover the opening portion 141. Specifically, as shown in FIGS. 5A and5B, one end of the insulating sheet 20 may be located between therear-surface-side protection member 14 and the sealing member 17, andthe other end of the insulating sheet 15 may be located near the centerof the opening portion 141 in a plan view. The base portion of theoutput leads 12 is fixed to a position by contacting the base portionagainst the other end of the insulating sheet 20. In this case, theother end of the insulating sheet 20 corresponds to a contact portion ofthe invention. The insulating sheet 20 may not be inserted between therear-surface-side protection member 14 and the sealing member 17, andmay be bonded on the surface of the rear-surface-side protection member14.

In the embodiment described above, one example has been used to describethe configuration of the solar cell module; however, the invention isnot limited to this configuration. For example, the solar cell module100 may be provided with thin-film solar cells laminated on thelight-receiving-surface-side protection member 13 in replace ofcrystalline solar cells 10 described above.

Although the following has not been mentioned in the embodimentdescribed above, a wiring member for bypass diode connection may bedrawn out along with the output lead 12 from the slit 151.

In the embodiment described above, the rear-surface-side protectionmember 14 has a configuration in which the metal layer is sandwichedbetween two resin layers; however the invention is not limited to thisconfiguration. For example, the rear-surface-side protection member 14may have three or more resin layers and may have two or more metallayers.

Thus, it should be understood that the invention includes variousembodiments not specifically described herein. Accordingly, thetechnical scope of the invention should be defined only by thespecifications of the invention according to the claims based on theabove description.

1. A solar cell module comprising: a solar cell having a light receivingsurface and a rear surface provided on the opposite side to the lightreceiving surface; a output lead configured to draw electric power fromthe solar cell; a light-receiving-surface-side protection memberdisposed on the light-receiving-surface-side of the solar cell; arear-surface-side protection member disposed on the rear-surface-side ofthe solar cell and having an opening portion through which the outputlead is drawn out; and an insulating sheet disposed on the openingportion; and wherein the rear-surface-side protection member includes ametal layer sandwiched between a plurality of resin layers, and theinsulating sheet includes a contact portion which is in contact with theoutput lead inside the opening portion in a plan view.
 2. The solar cellmodule according to claim 1, wherein the insulating sheet is formed of apair of sheets sandwiching the rear-surface-side protection member, andthe contact portion is a slit formed in the insulating sheet.
 3. Thesolar cell module according to claim 1, wherein the insulating sheetcovers the opening portion at the solar cell side of therear-surface-side protection member.
 4. The solar cell module accordingto claim 1, wherein the insulating sheet covers the opening portion atthe opposite side of the rear-surface-side protection member to thesolar cell.
 5. The solar cell module according to claim 4, wherein adistance between an outer edge of the insulating sheet and an outer edgeof the opening portion is greater than a thickness of therear-surface-side protection member.